Identity recognition plays an important role in numerous facets of life, including automatic banking services, e-commerce, e-banking, e-investing, e-data protection, remote access to resources, e-transactions, work security, anti-theft devices, criminologic identification, secure entry, and entry registration in the workplace.
Often computerized systems use passwords and personal identification numbers (PIN) for user recognition. But to maintain security, passwords have to be changed on a regular basis, imposing a substantial burden on the users. Likewise, signature verification methods suffer from other shortcomings, including forgery and enrollment fraud. See for example, U.S. Pat. No. 5,892,824 issued to Beatson et al.
As a result, identity recognition systems that use measures of an individual's biological phenomena—biometrics—have grown in recent years. Utilized alone or integrated with other technologies such as smart cards, encryption keys, and digital signatures, biometrics are expected to pervade nearly all aspects of the economy and our daily lives.
Several advanced technologies have been developed for biometric identification, including fingerprint recognition, retina and iris recognition, face recognition, and voice recognition. For example, Shockley et al., U.S. Pat. No. 5,534,855, generally describes using biometric data, such as fingerprints, to authorize computer access for individuals. Scheidt et al., U.S. Pat. No. 6,490,680, describes identity authentication using biometric data. Dulude et al., U.S. Pat. No. 6,310,966, describes the use of fingerprints, hand geometry, iris and retina scans, and speech patterns as part of a biometric authentication certificate. Murakami et al., U.S. Pat. No. 6,483,929, generally describes “physiological and histological markers,” including infra-red radiation, for biometric authentication. However, these types of technologies have penetrated only limited markets due to complicated and unfriendly acquisition modalities, sensitivity to environmental parameters (such as lighting conditions and background noise), and high cost. In addition, due to complicated acquisition procedures, the foregoing technologies usually require operator attendance.
Fingerprint recognition is well-established and the most mature technology of the group. But it has several drawbacks: a fingerprint recognition system cannot verify physical presence of the fingerprint owner and therefore is prone to deception, limiting its suitability for on-line applications; the optical sensor is a costly and fragile device generally unsuitable for consumer markets; and the system suffers from negative connotations related to criminology.
Retina scanning technologies are characterized by high performance. However, they require high-precision optical sensors, and are not user friendly because they require manipulation of head posture and operate on a very sensitive organ—the the human eye. The optical sensor is also costly and fragile.
Iris and face recognition systems are user-friendly technologies since they record an image from afar and are not intrusive. However, they require digital photographic equipment and are sensitive to lighting conditions, pupil size variations and facial expressions. In addition, iris recognition performance is degraded by the use of dark glasses and contact lens, and face recognition may be deceived by impersonation.
Voice recognition is the most user-friendly technology of the group; however, it requires a low-noise setting and is highly sensitive to intrinsically variable speech parameters, including intonation. Moreover, existing conventional recording technologies may be used to deceive speech-based recognition systems.
Thus, a need exists for reliable, robust, hard to deceive (on-line and off-line), low cost, user friendly identity recognition technologies that may be used in stand-alone applications or integrated with existing security systems.
Over the years, electrocardiogram (“ECG”) measurements have been used for many different purposes. ECG signals are electric signals generated by the heart and can be picked up using conventional surface electrodes, usually mounted on the subject's chest. ECG signals are made up of several components representative of different functional stages during each heart beat and projected according to the electric orientation of the generating tissues.
Individuals present different, subject-specific detail in their electro-cardiologic signals due to normal variations in the heart tissue structure, heart orientation, and electrical tissue orientation, all of which affect the electro-cardiologic signals measured from the limbs. Numerous types of systems make use of these subject-specific variations.
For example, Blazey-et al., U.S. Pat. No. 6,293,904, describes the use of ECG signals to evaluate or profile an individual's physiological and cognitive state. As to identification, a 2001 conference paper at the 23rd Annual International IEEE Conference on Engineering in Medicine and Biology Society (in Istanbul, Turkey) by Kyoso et al., entitled “Development of an ECG Identification System,” compares a patient's ECG with previously registered ECG feature parameters for purposes of identification. Wiederhold, U.S. Application No. 2003013509, suggests using directly or remotely acquired ECG signals to identify a subject, “explores” feature extraction for identifying individuals, and provides a “preliminary analysis” of such methods.
But an ECG signal is comprised of ECG components having features that may be common to a group. None of these references describe a system or method that eliminates common features of ECG components to create a signature for subject identification. Thus, there still exists a need for systems and methods with these attributes to identify an individual.
The inclusion of the foregoing references in this Background is not an admission that they are prior art or analogous art with respect to the inventions disclosed herein. All references in this Background section are, however, hereby incorporated by reference as though fully set out herein.